装配式钢筋混凝土叠合梁抗火性能研究  

Study on fire resistance of prefabricated concrete composite beams

作　　者：张大山[1] 胡浩灿 黄栋强 董毓利[1] 徐玉野[1] 王慧青 ZHANG Dashan;HU Haocan;HUANG Dongqiang;DONG Yuli;XU Yuye;WANG Huiqing(College of Civil Engineering,Huaqiao University,Xiamen 361021,China;College of Architecture and Civil Engineering,Xiamen Institute of Technology,Xiamen 361021,China)

机构地区：[1]华侨大学土木工程学院,福建厦门361021 [2]厦门工学院建筑科学与土木工程学院,福建厦门361021

出　　处：《建筑结构学报》2024年第2期25-37,共13页Journal of Building Structures

基　　金：国家自然科学基金项目(51978293,52178484);福建省自然科学基金项目(2023J01107);福建省中青年教师教育科研项目(JAT210570)。

摘　　要：为研究装配式建筑中由于两次浇筑混凝土而形成的叠合面对钢筋混凝土叠合梁抗火性能的影响,开展了3个钢筋混凝土叠合梁和2个钢筋混凝土整浇梁的火灾试验,研究荷载水平对叠合梁抗火性能的影响,并与整浇梁的抗火性能进行对比分析。火灾试验时,测试梁截面上的温度场、竖向挠度,观察梁在火灾下的试验现象和破坏特征。研究结果表明:火灾下,叠合梁和整浇梁在最大竖向挠度变形达到跨度的1/20时均未发生坍塌,但在临近停火前15 min具有较快的变形速度,呈现不稳定的平衡状态;在相同荷载水平下,叠合梁和整浇梁的耐火极限基本一致;叠合梁的叠合面上出现水平剥离裂缝,且在板块接缝处有一定程度的爆裂;以荷载比为0.3的叠合梁耐火极限149 min为基准,荷载比为0.5和0.7的叠合梁的耐火极限分别减少24.8%和41.6%,荷载比影响较为显著。基于试验结果,验证了基于弯矩-曲率关系曲线提出的耐火极限评估方法的有效性。To study the influence of interface between new and old concrete due to twice pouring on the fire resistance of prefabricate concrete composite beams(PCCBs),fire tests on three PCCBs and two reinforced concrete beams(RCBs)were conducted,especially to investigate the influence of load ratios on the fire resistance of PCCBs.The fire performance was compared between PCCBs and RCBs comprehensively.The temperature field data across the beam depth and vertical deflections were collected during the tests,and test phenomenon and typical failure patterns were recorded.It is shown that the maximum vertical deflection of both the PCCBs and RCBs under fire reaches 1/20 of the span-length,and no collapse is detected eventually.15 minutes before the furnace is shut down,a fast deflection speed is observed,showing an unstable working condition of beams.At the same load level,the PCCBs have a subequal duration of fire resistance with RCBs.After tests,a horizontal disjointed crack is observed and a certain concrete spalling is detected in the vicinity of inter-plate joints under the flange of slabs.For the PCCB with a load ratio of 0.3,the duration of fire resistance is 149 minutes.By contrast,the duration of fire resistance of the PCCBs with load ratio of 0.5 and 0.7 is reduced by 24.8%and 41.6%,respectively,which shows the impact of load ratio is significant.A calculation procedure was programed and verified to evaluate the duration of fire resistance of both PCCBs and RCBs based on the bending moment-curvature relationship.

关 键 词：装配式钢筋混凝土叠合梁 受火试验 荷载比 弯矩-曲率关系 耐火极限 

分 类 号：TU375.1[建筑科学—结构工程]